Nastavak članka "
Članak će razmotriti i pokazati na konkretnim upitima i primjerima koje se korisne informacije mogu dobiti korištenjem povijesti pogleda pg_locks.
Upozorenje.
Zbog novosti teme i nepotpunosti razdoblja testiranja, članak može sadržavati pogreške. Kritike i komentari su dobrodošli i očekivani.
Ulazni podaci
povijest reprezentacije pg_locks
zaključavanje_arhive
CREATE TABLE archive_locking
( timepoint timestamp without time zone ,
locktype text ,
relation oid ,
mode text ,
tid xid ,
vtid text ,
pid integer ,
blocking_pids integer[] ,
granted boolean ,
queryid bigint
);
U osnovi, stol je sličan stolu archive_pg_stat_activitydetaljnije opisano ovdje -
Za popunjavanje stupca queryid koristi se funkcija
update_history_locking_by_queryid
--update_history_locking_by_queryid.sql
CREATE OR REPLACE FUNCTION update_history_locking_by_queryid() RETURNS boolean AS $$
DECLARE
result boolean ;
current_minute double precision ;
start_minute integer ;
finish_minute integer ;
start_period timestamp without time zone ;
finish_period timestamp without time zone ;
lock_rec record ;
endpoint_rec record ;
current_hour_diff double precision ;
BEGIN
RAISE NOTICE '***update_history_locking_by_queryid';
result = TRUE ;
current_minute = extract ( minute from now() );
SELECT * FROM endpoint WHERE is_need_monitoring
INTO endpoint_rec ;
current_hour_diff = endpoint_rec.hour_diff ;
IF current_minute < 5
THEN
RAISE NOTICE 'Current time is less than 5 minute.';
start_period = date_trunc('hour',now()) + (current_hour_diff * interval '1 hour');
finish_period = start_period - interval '5 minute' ;
ELSE
finish_minute = extract ( minute from now() ) / 5 ;
start_minute = finish_minute - 1 ;
start_period = date_trunc('hour',now()) + interval '1 minute'*start_minute*5+(current_hour_diff * interval '1 hour');
finish_period = date_trunc('hour',now()) + interval '1 minute'*finish_minute*5+(current_hour_diff * interval '1 hour') ;
END IF ;
RAISE NOTICE 'start_period = %', start_period;
RAISE NOTICE 'finish_period = %', finish_period;
FOR lock_rec IN
WITH act_queryid AS
(
SELECT
pid ,
timepoint ,
query_start AS started ,
MAX(timepoint) OVER (PARTITION BY pid , query_start ) AS finished ,
queryid
FROM
activity_hist.history_pg_stat_activity
WHERE
timepoint BETWEEN start_period and
finish_period
GROUP BY
pid ,
timepoint ,
query_start ,
queryid
),
lock_pids AS
(
SELECT
hl.pid ,
hl.locktype ,
hl.mode ,
hl.timepoint ,
MIN ( timepoint ) OVER (PARTITION BY pid , locktype ,mode ) as started
FROM
activity_hist.history_locking hl
WHERE
hl.timepoint between start_period and
finish_period
GROUP BY
hl.pid ,
hl.locktype ,
hl.mode ,
hl.timepoint
)
SELECT
lp.pid ,
lp.locktype ,
lp.mode ,
lp.timepoint ,
aq.queryid
FROM lock_pids lp LEFT OUTER JOIN act_queryid aq ON ( lp.pid = aq.pid AND lp.started BETWEEN aq.started AND aq.finished )
WHERE aq.queryid IS NOT NULL
GROUP BY
lp.pid ,
lp.locktype ,
lp.mode ,
lp.timepoint ,
aq.queryid
LOOP
UPDATE activity_hist.history_locking SET queryid = lock_rec.queryid
WHERE pid = lock_rec.pid AND locktype = lock_rec.locktype AND mode = lock_rec.mode AND timepoint = lock_rec.timepoint ;
END LOOP;
RETURN result ;
END
$$ LANGUAGE plpgsql;
Objašnjenje: vrijednost stupca queryid ažurira se u tablici history_locking, a onda kada se kreira nova particija za tablicu archive_locking, vrijednost će biti pohranjena u povijesnim vrijednostima.
Izlaz
Opće informacije o procesima općenito.
ČEKANJE BRAVA PO VRSTAMA BRAVA
Zahtjev
WITH
t AS
(
SELECT
locktype ,
mode ,
count(*) as total
FROM
activity_hist.archive_locking
WHERE
timepoint between pg_stat_history_begin+(current_hour_diff * interval '1 hour') AND pg_stat_history_end+(current_hour_diff * interval '1 hour') AND
NOT granted
GROUP BY
locktype ,
mode
)
SELECT
locktype ,
mode ,
total * interval '1 second' as duration
FROM t
ORDER BY 3 DESC
Primjer
| ČEKANJE ZAKLJUČAVANJA PO VRSTAMA BRAVA +--------------------+------------------------ -------+-------------------- | vrsta zaključavanja| način| trajanje +--------------------+-------------------- ---+-- ------------------ | ID transakcije| sharelock| 19:39:26 | tuple| AccessExclusiveLock| 00:03:35 +--------------------+---------------------- -------+--------------------
OTIMANJE BRAVA PO VRSTAMA BRAVA
Zahtjev
WITH
t AS
(
SELECT
locktype ,
mode ,
count(*) as total
FROM
activity_hist.archive_locking
WHERE
timepoint between pg_stat_history_begin+(current_hour_diff * interval '1 hour') AND pg_stat_history_end+(current_hour_diff * interval '1 hour') AND
granted
GROUP BY
locktype ,
mode
)
SELECT
locktype ,
mode ,
total * interval '1 second' as duration
FROM t
ORDER BY 3 DESC
Primjer
| UZIMANJE BRAVA PO VRSTAMA BRAVA +---------------------+------------------------ -------+-------------------- | vrsta zaključavanja| način| trajanje +--------------------+-------------------- ---+-- ------------------ | odnos| RowExclusiveLock| 51:11:10 | virtualxid| ExclusiveLock| 48:10:43 | ID transakcije| ExclusiveLock| 44:24:53 | odnos| AccessShareLock| 20:06:13 | tuple| AccessExclusiveLock| 17:58:47 | tuple| ExclusiveLock| 01:40:41 | odnos| ShareUpdateExclusiveLock| 00:26:41 | objekt| RowExclusiveLock| 00:00:01 | ID transakcije| sharelock| 00:00:01 | proširiti| ExclusiveLock| 00:00:01 +---------------------+------------------------ -------+--------------------
Detaljne informacije za specifične queryid upite
ČEKA SE ZAKLJUČAVANJA PO VRSTAMA ZAKLJUČAVANJA PO IDU UPITA
Zahtjev
WITH
lt AS
(
SELECT
pid ,
locktype ,
mode ,
timepoint ,
queryid ,
blocking_pids ,
MIN ( timepoint ) OVER (PARTITION BY pid , locktype ,mode ) as started
FROM
activity_hist.archive_locking
WHERE
timepoint between pg_stat_history_begin+(current_hour_diff * interval '1 hour') AND
pg_stat_history_end+(current_hour_diff * interval '1 hour') AND
NOT granted AND
queryid IS NOT NULL
GROUP BY
pid ,
locktype ,
mode ,
timepoint ,
queryid ,
blocking_pids
)
SELECT
lt.pid ,
lt.locktype ,
lt.mode ,
lt.started ,
lt.queryid ,
lt.blocking_pids ,
COUNT(*) * interval '1 second' as duration
FROM lt
GROUP BY
lt.pid ,
lt.locktype ,
lt.mode ,
lt.started ,
lt.queryid ,
lt.blocking_pids
ORDER BY 4
Primjer
| ČEKA SE ZAKLJUČAVANJA PO VRSTAMA ZAKLJUČAVANJA PO QUERYID-u +----------+-------------------------+----- ---------------+------------------------------+--- ------------------+--------------------+---------- - --------- | pid| vrsta zaključavanja| način| započeo| ID upita| blokiranje_pids| trajanje +----------+------------------------+----------- ---------+------------------------------+--------- ---+--------------------+---------------- --- | 11288| ID transakcije| sharelock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34 | 11626| ID transakcije| sharelock| 2019-09-17 10:00:21.380921| 389015618226997618| {12380}| 00:00:29 | 11626| ID transakcije| sharelock| 2019-09-17 10:00:21.380921| 389015618226997618| {11092}| 00:03:25 | 11626| ID transakcije| sharelock| 2019-09-17 10:00:21.380921| 389015618226997618| {12213}| 00:01:55 | 11626| ID transakcije| sharelock| 2019-09-17 10:00:21.380921| 389015618226997618| {12751}| 00:00:01 | 11629| ID transakcije| sharelock| 2019-09-17 10:00:24.331935| 389015618226997618| {11092}| 00:03:22 | 11629| ID transakcije| sharelock| 2019-09-17 10:00:24.331935| 389015618226997618| {12007}| 00:00:01 | 12007| ID transakcije| sharelock| 2019-09-17 10:05:03.327933| 389015618226997618| {11629}| 00:00:13 | 12007| ID transakcije| sharelock| 2019-09-17 10:05:03.327933| 389015618226997618| {11092}| 00:01:10 | 12007| ID transakcije| sharelock| 2019-09-17 10:05:03.327933| 389015618226997618| {11288}| 00:00:05 | 12213| ID transakcije| sharelock| 2019-09-17 10:06:07.328019| 389015618226997618| {12007}| 00:00:10
UZIMANJE BRAVA PO VRSTAMA BRAVA PREMA QUERYID-u
Zahtjev
WITH
lt AS
(
SELECT
pid ,
locktype ,
mode ,
timepoint ,
queryid ,
blocking_pids ,
MIN ( timepoint ) OVER (PARTITION BY pid , locktype ,mode ) as started
FROM
activity_hist.archive_locking
WHERE
timepoint between pg_stat_history_begin+(current_hour_diff * interval '1 hour') AND
pg_stat_history_end+(current_hour_diff * interval '1 hour') AND
granted AND
queryid IS NOT NULL
GROUP BY
pid ,
locktype ,
mode ,
timepoint ,
queryid ,
blocking_pids
)
SELECT
lt.pid ,
lt.locktype ,
lt.mode ,
lt.started ,
lt.queryid ,
lt.blocking_pids ,
COUNT(*) * interval '1 second' as duration
FROM lt
GROUP BY
lt.pid ,
lt.locktype ,
lt.mode ,
lt.started ,
lt.queryid ,
lt.blocking_pids
ORDER BY 4
Primjer
| ZAKLJUČAVANJE PO VRSTAMA BRAVA PREMA QUERYID-u +----------+-------------------------+------ --------------+------------------------------+---- -+--------------------+------------ -------- | pid| vrsta zaključavanja| način| započeo| ID upita| blokiranje_pids| trajanje +----------+------------------------+----------- ---------+------------------------------+--------- ---+--------------------+---------------- --- | 11288| odnos| RowExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34 | 11092| ID transakcije| ExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {}| 00:03:34 | 11288| odnos| RowExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {}| 00:00:10 | 11092| odnos| RowExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {}| 00:03:34 | 11092| virtualxid| ExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {}| 00:03:34 | 11288| virtualxid| ExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34 | 11288| ID transakcije| ExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34 | 11288| tuple| AccessExclusiveLock| 2019-09-17 10:00:00.302936| 389015618226997618| {11092}| 00:03:34
Korištenje povijesti blokiranja pri analizi incidenata performansi.
- Upit s queryid=389015618226997618 koji je izvršio proces s pid=11288 čeka na zaključavanje od 2019-09-17 10:00:00 3 minute.
- Zaključavanje je držao proces s pid=11092
- Proces s pid=11092 koji izvršava upit s queryid=389015618226997618 od 2019. rujna 09. u 17:10:00 držao je zaključavanje 00 minute.
Ukupan
Sada će, nadam se, početi najzanimljivija i najkorisnija stvar - prikupljanje statistike i analiza slučajeva o povijesti očekivanja i blokiranja.
U budućnosti, volio bih vjerovati, dobit ćete skup nekakvih bilješki (slično Oracleovom metalinku).
Općenito, iz tog je razloga korištena metodologija prikazana što je prije moguće za javno upoznavanje.
U vrlo bliskoj budućnosti pokušat ću staviti projekt na github.
Izvor: www.habr.com